Pd/Ce_xZr_(1-x)O_2对柴油机尾气中可溶性有机物的催化氧化性能

The catalytic oxidation of SOF in diesel engine exhaust by Pd/Ce_xZr_(1-x)O_2 catalysts

采用共沉淀结合乙醇超临界干燥方法,制备了不同铈锆比的CexZr1-xO2复合氧化物,采用浸渍法制备了负载Pd的催化剂,通过XRD、N2吸脱附、H2-TPR和静态储氧量测试等表征技术,考察了它们的结构性质、还原性能和储放氧性能,并将其应用于柴油机尾气可溶性有机物(SOF)的催化氧化反应中.结果表明,该铈锆复合氧化物具有圆柱形管状介孔结构,孔径分布范围较宽,具有较大的比表面积,因而有利于对SOF的吸附;锆的添加使铈锆复合氧化物体相氧向表面迁移的能力增强,进而提高了载体及其负载Pd催化剂的储氧量、还原性能和对SOF的催化氧化性能.

Ceria-zirconias with different Ce/Zr ratios were prepared by co-precipitation route using alcohol-supercritical drying method,and their Pd loaded catalysts were prepared by impregnation.Their performance in the catalytic oxidation of soluble organic fraction（SOF）were investigated.The properties of ceria-zirconias and their Pd loaded catalysts,such as structures,reducibility and oxygen storage capacity were charactered by XRD,N2adsorption-desorption measurement,H2-TPR and OSCC measurement techniques.Results show as follows,the ceria-zirconias have cylindrical tubular mesopore structure,wide pore distribution range and fair size BET surface area.These are beneficial to the adsorption of SOF;The addition of Zr enhaces the migration of bulk oxygen to the surface of Ceria-Zirconias,which improves the oxygen storage capacity,reducibility and oxidation ability in SOF of ceria-zirconias and their Pd loaded catalysts.